8.1 Volvo Overheating

[tjh408]

I have 8.1 Volvo's with 600 hours in a 2003, 360 SS. The port engine runs hotter than It should. At one point it ran up to 240 on the gauge. I have replaced the raw water pump, flushed the raw water side with dock water, removed the end caps from the heat exchanger and flushed it. It still runs warmer than the starboard side. I understand the gauges aren't really calibrated on these and only show 100 and 240 on them. Just looking for more suggestions. It cools down once it the RPM is up over about 1,200. That can be tough in no wake zones!

Thanks

[g36]

checked or replaced themostat?

[tjh408]

Not yet, that will be a real tough one up close under the galley floor! Plan to shoot it this W/E with a IR thermometer.

[bud37]

Couple questions....if you run the engine at the dock at idle then over 1200 , does the same thing happen with the temps.

You on salt, critters in the intake ?

You know from your description ( cooler with more rpm ), it almost sounds like the engine circulation pump, but check the thermostat first.....maybe sticking.

Also double checking the temp gages is a real good idea....there could be a lot of tail chasing if the sending unit/gage is bad and that is all it is......good luck man....hope it is the simple stuff.

[tjh408]

Yes it will cool down at the dock at 1200. Yes in salt, however I have back-flushed the raw water side with dock water pretty well. It hard to tell the actual discharge, as it is under the boat on this model vs side exhaust. I have flushed it through all the lines. T-stat and gauge are next.

I have been told about a blue flush cap for fresh water that sometimes leaks air and creates problems?

Thanks

[tjh408]

It appears that it is cooling OK. After running it for extended periods at the dock and shooting it with a IR thermometer I don't see it getting over 165 - 170 anywhere on the motor or cooling system. The t-stat housing gets to 170, the heat exchanger 155. I ran it this weekend, gauges ran to just above 1/2 most of the time, after running at 3200 for a little while (30 mins) they would run to 3/4 in the no wake zone. Then eventually back to just above 1/2.